1. Field
Example embodiments relate to a method and apparatus for data communication, and for example, to a signal transceiver for differential data communication of ternary data using three transmission lines and/or a method therefor.
2. Description of Related Art
Binary data communication is usually performed using a single-ended interface in which a signal of a transmission line corresponds to a bit of binary data. A binary single-ended interface is effectively used in a noiseless environment. However, in an environment where a width of a voltage swing is decreased in order to obtain higher-speed data transmission, the binary single-ended interface may not accurately receive data due to noise. Therefore, a differential-ended interface, in which a differential signal is transmitted by using two transmission lines, has been developed. The differential-ended interface transmits two statuses, i.e., 1-bit data using two transmission lines.
The differential-ended interface has ½ the data transmission efficiency, i.e., the differential-ended interface has a data transmission efficiency of a bit number of data divided by a number of transmission lines. In order to implement higher data transmission efficiency, a method and apparatus for transmitting a differential signal using an electric current loop have been developed.
FIG. 1 is a diagram illustrating a conventional differential signal transceiver.
Referring to FIG. 1, the differential signal transceiver uses three transmission lines 330a, 330b, and 330c to transmit data from a signal transmission unit 310 to a signal reception unit 320. The signal reception unit 320 receives a signal generated from the signal transmission unit 310 through a plurality of ports Pa, Pb, and Pc. First through third matching means 340a, 340b, and 340c are respectively connected between the ports Pa, Pb, and Pc.
In the signal reception unit 320, voltage magnitudes of the ports Pa, Pb, and Pc may vary in accordance with a direction of an electric current of the first through third matching means 340a, 340b, and 340c. The signal reception unit 320 recognizes six statuses of data in accordance with the orders of the voltage magnitudes of the ports Pa, Pb, and Pc.
FIG. 2 is a detailed diagram of the signal reception unit 320 illustrated in FIG. 1.
If the direction of the electric current is Pc→Pb→Pa, the voltage magnitudes of the ports Pa, Pb, and Pc are Vc>Vb>Va, which is referred to as a first status. If the direction of the electric current is Pb→Pa→Pc, the voltage magnitudes of the ports Pa, Pb, and Pc are Vb>Va>Vc, which is referred to as a second status. If the direction of the electric current is Pb→Pc→Pa, the voltage magnitudes of the ports Pa, Pb, and Pc are Vb>Vc>Va, which is referred to as a third status. If the direction of the electric current is Pa→Pc→Pb, the voltage magnitudes of the ports Pa, Pb and Pc are Va>Vc>Vb, which is referred to as a fourth status. If the direction of the electric current is Pc→Pa→Pb, the voltage magnitudes of the ports Pa, Pb and Pc are Vc>Va>Vb, which is referred to as a fifth status. If the direction of the electric current is Pa→Pb→Pc, the voltage magnitudes of the ports Pa, Pb and Pc are Va>Vb>Vc, which is referred to as a sixth status.
The six statuses, i.e., data having six patterns, are 2.58-bit data and the data transmission efficiency is improved to 2.58/3. However, the above described conventional differential signal transceiver cannot completely transmit 3-bit data having eight patterns.